Apparatus and method for treating aqueous solutions and contaminants therein

ABSTRACT

The present disclosure is generally directed to devices and methods of treating aqueous solutions to help remove or otherwise reduce levels, concentrations or amounts of one or more contaminants. The present disclosure relates to a apparatus including a substantially self-contained housing or container which is adapted to receive components including at least one counterelectrode (e.g. cathode) and at least one photoelectrode (e.g. anode) provided or arranged around at least one UV light source, and/or receive, contain and/or circulate fluid or aqueous solution.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. ProvisionalPatent Application Ser. No. 61/566,490, filed Dec. 2, 2011, and U.S.Provisional Patent Application Ser. No. 61/584,012, filed Jan. 6, 2012,each which is hereby incorporated herein by reference in its entirety.

BACKGROUND

Aqueous solutions often contain one or more contaminants. Such aqueoussolutions include, but are not limited to, hydraulic fracturing fluid,hydraulic fracturing backflow water, high-salinity solutions,groundwater, seawater, wastewater, drinking water, aquaculture (e.g.,aquarium water and aquaculture water), ballast water, and textileindustry dye waste water. Further information of example aqueoussolutions follows.

Hydraulic fracturing fluid includes any fluid or solution utilized tostimulate or produce gas or petroleum, or any such fluid or solutionafter it is used for that purpose.

Groundwater includes water that occurs below the surface of the Earth,where it occupies spaces in soils or geologic strata. Groundwater mayinclude water that supplies aquifers, wells and springs.

Wastewater may be any water that has been adversely affected in qualityby effects, processes, and/or materials derived from human or non-humanactivities. For example, wastewater may be water used for washing,flushing, or in a manufacturing process, that contains waste products.Wastewater may further be sewage that is contaminated by feces, urine,bodily fluids and/or other domestic, municipal or industrial liquidwaste products that is disposed of (e.g., via a pipe, sewer, or similarstructure or infrastructure or via a cesspool emptier). Wastewater mayoriginate from blackwater, cesspit leakage, septic tanks, sewagetreatment, washing water (also referred to as “graywater”), rainfall,groundwater infiltrated into sewage, surplus manufactured liquids, roaddrainage, industrial site drainage, and storm drains, for example.

Drinking water includes water intended for supply, for example, tohouseholds, commerce and/or industry. Drinking water may include waterdrawn directly from a tap or faucet. Drinking water may further includesources of drinking water supplies such as, for example, surface waterand groundwater.

Aquarium water includes, for example, freshwater, seawater, andsaltwater used in water-filled enclosures in which fish or other aquaticplants and animals are kept or intended to be kept. Aquarium water mayoriginate from aquariums of any size such as small home aquariums up tolarge aquariums (e.g., aquariums holding thousands to hundreds ofthousands of gallons of water).

Aquaculture water is water used in the cultivation of aquatic organisms.Aquaculture water includes, for example, freshwater, seawater, andsaltwater used in the cultivation of aquatic organisms.

Ballast water includes water, such as freshwater and seawater, held intanks and cargo holds of ships to increase the stability andmaneuverability during transit. Ballast water may also contain exoticspecies, alien species, invasive species, and/or nonindiginous speciesof organisms and plants, as well as sediments and contaminants.

A contaminant may be, for example, an organism, an organic chemical, aninorganic chemical, and/or combinations thereof. More specifically,“contaminant” may refer to any compound that is not naturally found inan aqueous solution. Contaminants may also include microorganisms thatmay be naturally found in an aqueous solution and may be considered safeat certain levels, but may present problems (e.g., disease and/or otherhealth problems) at different levels. In other cases (e.g., in the caseof ballast water), contaminants also include microorganisms that may benaturally found in the ballast water at its point of origin, but may beconsidered non-native or exotic species. Moreover, governmental agenciessuch as the United States Environmental Protection Agency, haveestablished standards for contaminants in water.

A contaminant may include a material commonly found in hydraulicfracturing fluid before or after use. For example, the contaminant maybe one or more of the following or combinations thereof: diluted acid(e.g., hydrochloric acid), a friction reducer (e.g., polyacrylamide), anantimicrobial agent (e.g. glutaraldehyde, ethanol, and/or methanol),scale inhibitor (e.g. ethylene glycol, alcohol, and sodium hydroxide),sodium and calcium salts, barium, oil, strontium, iron, heavy metals,soap, bacteria, etc. A contaminant may include a polymer to thicken orincrease viscosity to improve recovery of oil. A contaminant may alsoinclude guar or guar gum, which is commonly used as a thickening agentin many applications in oil recovery, the energy field, and the foodindustry.

A contaminant may be an organism or a microorganism. The microorganismmay be for example, a prokaryote, a eukaryote, and/or a virus. Theprokaryote may be, for example, pathogenic prokaryotes and fecalcoliform bacteria. Example prokaryotes may be Escherichia, Brucella,Legionella, sulfate reducing bacteria, acid producing bacteria, Cholerabacteria, and combinations thereof.

Example eukaryotes may be a protist, a fungus, or an algae. Exampleprotists (protozoans) may be Giardia, Cryptosporidium, and combinationsthereof. A eukaryote may also be a pathogenic eukaryote. Alsocontemplated within the disclosure are cysts of cyst-forming eukaryotessuch as, for example, Giardia.

A eukaryote may also include one or more disease vectors. A “diseasevector” refers any agent (person, animal or microorganism) that carriesand transmits an infectious pathogen into another living organism.Examples include, but are not limited to, an insect, nematode, or otherorganism that transmits an infectious agent. The life cycle of someinvertebrates such as, for example, insects, includes time spent inwater. Female mosquitoes, for example, lay their eggs in water. Otherinvertebrates such as, for example, nematodes, may deposit eggs inaqueous solutions. Cysts of invertebrates may also contaminate aqueousenvironments. Treatment of aqueous solutions in which a vector (e.g.,disease vector) may reside may thus serve as a control mechanism forboth the disease vector and the infectious agent.

A contaminant may be a virus. Example viruses may include a waterbornevirus such as, for example, enteric viruses, hepatitis A virus,hepatitis E virus, rotavirus, and MS2 coliphage, adenovirus, andnorovirus.

A contaminant may include an organic chemical. The organic chemical maybe any carbon-containing substance according to its ordinary meaning.The organic chemical may be, for example, chemical compounds,pharmaceuticals, over-the-counter drugs, dyes, agricultural pollutants,industrial pollutants, proteins, endocrine disruptors, fuel oxygenates,and/or personal care products. Examples of organic chemicals may includeacetone, acid blue 9, acid yellow 23, acrylamide, alachlor, atrazine,benzene, benzo(a)pyrene, bromodichloromethane, carbofuran, carbontetrachloride, chlorobenzene, chlorodane, chloroform, chloromethane,2,4-dichlorophenoxyacetic acid, dalapon, 1,2-dibromo-3-chloropropane,o-dichlorobenzene, p-dichlorobenzene, 1,2-dichloroethane,1,1-dichloroethylene, cis-1,2-dichloroethylene,trans-1,2-dichloroethylene, dichlormethane, 1,2-dichloropropane,di(2-ethylhexyl)adipate, di(2-ethylhexyl)phthalate, dinoseb, dioxin(2,3,7,8-TCDD), diquat, endothall, endrin, epichlorohydrin,ethylbenzene, ethylene dibromide, glyphosate, a haloacetic acid,heptachlor, heptachlor epoxide, hexachlorobenzene,hexachlorocyclopentadiene, lindane, methyl-tertiary-butyl ether,methyoxychlor, napthoxamyl (vydate), naphthalene, pentachlorophenol,phenol, picloram, isopropylbenzene, N-butylbenzene, N-propylbenzene,Sec-butylbenzene, polychlorinated biphenyls (PCBs), simazine, sodiumphenoxyacetic acid, styrene, tetrachloroethylene, toluene, toxaphene,2,4,5-TP (silvex), 1,2,4-trichlorobenzene, 1,1,1-trichloroethane,1,1,2-trichloroethane, trichloroethylene, a trihalomethane,1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, vinyl chloride,o-xylene, m-xylene, p-xylene, an endocrine disruptor, a G-series nerveagent, a V-series nerve agent, bisphenol-A, bovine serum albumin,carbamazepine, cortisol, estradiol-17β, gasoline, gelbstoff, triclosan,ricin, a polybrominated diphenyl ether, a polychlorinated diphenylether, and a polychlorinated biphenyl. Methyl tert-butyl ether (alsoknown as, methyl tertiary-butyl ether) is a particularly applicableorganic chemical contaminant.

A contaminant may include an inorganic chemical. More specifically, thecontaminant may be a nitrogen-containing inorganic chemical such as, forexample, ammonia (NH₃) or ammonium (NH₄). Contaminants may includenon-nitrogen-containing inorganic chemicals such as, for example,aluminum, antimony, arsenic, asbestos, barium, beryllium, bromate,cadmium, chloramine, chlorine, chlorine dioxide, chlorite, chromium,copper, cyanide, fluoride, iron, lead, manganese, mercury, nickel,nitrate, nitrite, selenium, silver, sodium, sulfate, thallium, and/orzinc.

A contaminant may include a radionuclide. Radioactive contamination maybe the result of a spill or accident during the production or use ofradionuclides (radioisotopes). Example radionuclides include, but arenot limited to, an alpha photon emitter, a beta photon emitter, radium226, radium 228, and uranium.

Various methods exist for handling contaminants and contaminated aqueoussolutions. Generally, for example, contaminants may be contained toprevent them from migrating from their source, removed, and immobilizedor detoxified.

Another method for handling contaminants and contaminated aqueoussolutions is to treat the aqueous solution at its point-of-use.Point-of-use water treatment refers to a variety of different watertreatment methods (physical, chemical and biological) for improvingwater quality for an intended use such as, for example, drinking,bathing, washing, irrigation, etc., at the point of consumption insteadof at a centralized location. Point-of-use treatment may include watertreatment at a more decentralized level such as a small community or ata household. A drastic alternative is to abandon use of the contaminatedaqueous solutions and use an alternative source.

Other methods for handling contaminants and contaminated aqueoussolutions are used for removing gasoline and fuel contaminants, andparticularly the gasoline additive, MTBE. These methods include, forexample, phytoremediation, soil vapor extraction, multiphase extraction,air sparging, membranes (reverse osmosis), and other technologies. Inaddition to high cost, some of these alternative remediationtechnologies result in the formation of other contaminants atconcentrations higher than their recommended limits. For example, mostoxidation methods of MTBE result in the formation of bromate ions higherthan its recommended limit of 10 μg/L in drinking water (Liang et al.,“Oxidation of MTBE by ozone and peroxone processes,” J. Am. Water WorksAssoc. 91:104 (1999)).

A number of technologies have proven useful in reducing MTBEcontamination, including photocatalytic degradation with UV light andtitanium dioxide (Barreto et al., “Photocatalytic degradation of methyltert-butyl ether in TiO₂ slurries: a proposed reaction scheme,” WaterRes. 29:1243-1248 (1995); Cater et al., UV/H₂O₂ treatment of MTBE incontaminated water,” Environ. Sci Technol. 34:659 (2000)), oxidationwith UV and hydrogen peroxide (Chang and Young, “Kinetics of MTBEdegradation and by-product formation during UV/hydrogen peroxide watertreatment,” Water Res. 34:2223 (2000); Stefan et al., Degradationpathways during the treatment of MTBE by the UV/H₂O₂ process,” Environ.Sci. Technol. 34:650 (2000)), oxidation by ozone and peroxone (Liang etal., “Oxidation of MTBE by ozone and peroxone processes,” J. Am. WaterWorks Assoc. 91:104 (1999)) and in situ and ex situ bioremediation(Bradley et al., “Aerobic mineralization of MTBE and tert-Butyl alcoholby stream bed sediment microorganisms,” Environ. Sci. Technol.33:1877-1879 (1999)).

Use of titanium dioxide (titania, TiO₂) as a photocatalyst has beenshown to degrade a wide range of organic pollutants in water, includinghalogenated and aromatic hydrocarbons, nitrogen-containing heterocycliccompounds, hydrogen sulfide, surfactants, herbicides, and metalcomplexes (Matthews, “Photo-oxidation of organic material in aqueoussuspensions of titanium dioxide,” Water Res. 220:569 (1986); Matthews,“Kinetic of photocatalytic oxidation of organic solutions overtitanium-dioxide,” J. Catal. 113:549 (1987); Ollis et al., “Destructionof water contaminants,” Environ. Sci. Technol. 25:1522 (1991)).

Irradiation of a semiconductor photocatalyst, such as titanium dioxide(TiO₂), zinc oxide, or cadmium sulfide, with light energy equal to orgreater than the band gap energy (Ebg) causes electrons to shift fromthe valence band to the conduction band. If the ambient and surfaceconditions are correct, the excited electron and hole pair canparticipate in oxidation-reduction reactions. The oxygen acts as anelectron acceptor and forms hydrogen peroxide. The electron donors(i.e., contaminants) are oxidized either directly by valence band holesor indirectly by hydroxyl radicals (Hoffman et al., “Photocatalyticproduction of H₂O₂ and organic peroxide on quantum-sized semi-conductorcolloids,” Environ. Sci. Technol. 28:776 (1994)). Additionally, etherscan be degraded oxidatively using a photocatalyst such as TiO₂ (Lichtinet al., “Photopromoted titanium oxide-catalyzed oxidative decompositionof organic pollutants in water and in the vapor phase,” Water Pollut.Res. J. Can. 27:203 (1992)). A reaction scheme for photocatalyticallydestroying MTBE using UV and TiO₂ has been proposed, butphotodegradation took place only in the presence of catalyst, oxygen,and near UV irradiation and MTBE was converted to several intermediates(tertiary-butyl formate, tertiary-butyl alcohol, acetone, andalpha-hydroperoxy MTBE) before complete mineralization (Barreto et al.“Photocatalytic degradation of methyl tert-butyl ether in TiO₂ slurries:a proposed reaction scheme,” Water Res. 29:1243-1248 (1995)).

A more commonly used method of treating aqueous solutions fordisinfection of microorganisms is chemically treating the solution withchlorine. Disinfection with chlorine, however, has severaldisadvantages. For example, chlorine content must be regularlymonitored, formation of undesirable carcinogenic by-products may occur,chlorine has an unpleasant odor and taste, and chlorine requires thestorage of water in a holding tank for a specific time period.

Aqueous solutions used for hydraulically fracturing gas wells (e.g.,fracturing or frac fluids) or otherwise stimulating petroleum, oiland/or gas production also require treatment. Such solutions or fracfluids typically include one or more components or contaminantsincluding, by way of example and without limitation, water, sand,diluted acid (e.g., hydrochloric acid), one or more polymers or frictionreducers (e.g., polyacrylamide), one or more antimicrobial agents (e.g.glutaraldehyde, ethanol, and/or methanol), one or more scale inhibitors(e.g. ethylene glycol, alcohol, and sodium hydroxide), and one or morethickening agents (e.g., guar). In addition, a significant percentage ofsuch solutions and fluids return toward the Earth surface as flowback,and later as produced water, after they have been injected into ahydrofrac zone underground. As they return toward the Earth surface, thesolutions and fluids also pick up other contaminants from the earth suchas salt (e.g., sodium and calcium salts). Such fluids may also includebarium, oil, strontium, iron, heavy metals, soap, high concentrations ofbacteria including acid producing and sulfate reducing bacteria, etc.

Aqueous solutions used for hydraulically fracturing gas wells orotherwise stimulating oil and gas production are difficult and expensiveto treat for many reasons including, without limitation, the salinity ofthe solutions. For that reason, such fluids are often ultimatelydisposed of underground, offsite, or into natural water bodies. In somecases, certain states and countries will not allow fracking due toremediation concerns.

Accordingly, there is a need in the art for alternative approaches fortreating aqueous solutions to remove and/or reduce amounts ofcontaminants. Specifically, it would be advantageous to have apparatusand/or methods for treating various aqueous solutions includinghydraulic fracturing fluid, hydraulic fracturing backflow water,high-salinity water, groundwater, seawater, wastewater, drinking water,aquarium water, and aquaculture water, and/or for preparation ofultrapure water for laboratory use and remediation of textile industrydye waste water, among others, that help remove or eliminatecontaminants without the addition of chemical constituents, theproduction of potentially hazardous by-products, or the need forlong-term storage.

SUMMARY

The present disclosure is generally directed to devices and methods oftreating aqueous solutions to help remove or otherwise reduce levels oramounts of one or more contaminants. More specifically, the presentdisclosure relates to an apparatus for removing or reducing the level ofcontaminants in a solution comprising a housing having first opposingend and a second opposing end and at least partially defining a cavityhaving a cavity wall and a cavity length; a light tube provided withinthe cavity and adapted to help disburse or otherwise provide ultravioletradiation over most of the cavity length; a photoelectrode providedaround the light tube; a counterelectrode provided in the space betweenthe photoelectrode and the cavity wall, and a separator provided betweenthe photoelectrode and counterelectrode; wherein the photoelectrodecomprises a primarily titanium foil support with a layer of titaniumdioxide provided on at least one surface the photoelectrode; and whereinthe photoelectrode and counterelectrode are each coupled to a respectiveterminal adapted to be electrically coupled to a power supply.

The present invention further relates to a method for removing orreducing the level of contaminants in a solution comprising providing asolution into a cavity of a device, wherein the cavity of the devicehouses a light tube, a photoelectrode comprising a primarily titaniumfoil support with a layer of titanium dioxide provided thereon providedaround the light tube, and a counterelectrode provided in the spacebetween the photoelectrode and a cavity wall of the device; irradiatingthe photoelectrode with ultraviolet light; and applying a first bias toa first terminal coupled to the photoelectrode and a second terminalcoupled to a counterelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be better understood, and features, aspects andadvantages other than those set forth above will become apparent whenconsideration is given to the following detailed description thereof.Such detailed description makes reference to the following drawings,wherein:

FIG. 1 is an isometric view of a device or apparatus, according to oneor more examples of embodiments.

FIG. 2 is an isometric view of the device or apparatus illustrated inFIG. 1, according to one or more examples of embodiments.

FIG. 3 is an isometric cross-sectional view of a device or apparatus,according to one or more examples of embodiments.

FIG. 4 is an isometric view of a photoelectrode provided around (e.g.,partially around for purposes of illustration) a light tube or sleeveprovided in an end cap, according to one or more examples ofembodiments.

FIG. 5 is a partial isometric view of a device or apparatus, accordingto one or more examples of embodiments.

FIG. 6 is an exploded view of an electrical or terminal configuration ofthe device or apparatus illustrated in FIG. 5, according to one or moreexamples of embodiments.

FIG. 7 is an exploded isometric view of a device or apparatus, accordingto one or more examples of embodiments.

FIG. 8 is a side view of the device or apparatus illustrated in FIG. 7,according to one or more examples of embodiments.

FIG. 9 is a top view of the device or apparatus illustrated in FIG. 7according to one or more examples of embodiments.

FIG. 10 is an end view of the device or apparatus illustrated in FIG. 7,according to one or more examples of embodiments.

FIG. 11 is a partial cross-sectional isometric view of a device orapparatus, according to one or more examples of embodiments.

FIG. 12 is a partial cross-sectional isometric view of a device orapparatus, according to one or more examples of embodiments.

FIG. 13 is a partial cross-sectional view of the device or apparatusillustrated in FIG. 12, according to one or more examples ofembodiments.

FIG. 14 is a partial cross-sectional view of a device or apparatus,according to one or more examples of embodiments.

FIG. 15 is an isometric view of a spacer, according to one or moreexamples of embodiments.

FIG. 16 is an exit end view of the spacer illustrated in FIG. 15,according to one or more examples of embodiments.

FIG. 17 is an entrance end view of the spacer illustrated in FIG. 15,according to one or more examples of embodiments.

FIG. 18 is a cross-sectional view of the spacer illustrated in FIG. 15,according to one or more examples of embodiments.

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described below in detail. Forexample, any numbers, measurements, and/or dimensions illustrated in theFigures are for purposes of example only. Any number, measurement ordimension suitable for the purposes provided herein may be acceptable.It should be understood that the description of specific embodiments isnot intended to limit the disclosure from covering all modifications,equivalents and alternatives falling within the spirit and scope of thedisclosure.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the disclosure belongs. Although any methods andmaterials similar to or equivalent to those described herein may be usedin the practice or testing of the present disclosure, example methodsand materials are described below.

Various embodiments of system, apparatus, and device (e.g., aphotoelectric catalytic oxidation (PECO) system, apparatus, and device)are described. In various embodiments, the device includes and/or isprovided in an apparatus or reactor or substantially self-containeddevice. The device or reactor in various embodiments includes a housingor container which is adapted to receive components (e.g. operativecomponents) of the device and/or receive, contain and/or circulate fluidor aqueous solution. In various embodiments, the container houses atleast one counterelectrode (e.g. cathode) and at least onephotoelectrode (e.g. anode) provided or arranged around at least one UVlight source. In various embodiments, a counterelectrode (e.g. cathode),a photoelectrode (e.g. anode), and a UV light source may be provided ina structure, such as a tubular or annular housing or container. Invarious embodiments, flow of fluid or solution is facilitated past thephotoelectrode and counterelectrode. In various embodiments, one or morepower supplies and/or ballasts are included or provided for powering theUV-light source and/or for providing electrical potential to one or moreof the counterelectrodes (e.g., cathodes) and photoelectrodes (e.g.,anodes). In various embodiments, one or more power supplies and/orballasts are electrically coupled to UV-light sources and/or electrodes,but provided externally to the container, housing or device.

Generally, in various embodiments, a method for reducing the level oramount of one or more contaminants in solution or fluid describedincludes introducing the solution into a housing or container or cellincluding: a UV light; a photoelectrode (e.g., anode), wherein thephotoelectrode comprises an anatase polymorph of titanium, a rutilepolymorph of titanium, or a nanoporous film of titanium dioxide; and acounterelectrode (e.g., cathode). In various embodiments, thephotoelectrode is irradiated with UV light, and a first potential orbias is applied to the photoelectrode and counterelectrode for a firstperiod of time. In various embodiments, a second potential or bias isapplied to the photoelectrode and counterelectrode for a second periodof time. As a result, in various embodiments, a contaminant level oramount in solution is reduced.

An example of a device or apparatus (e.g., photoelectrocatalyticoxidation (PECO) device or apparatus) 100 according to one or moreexamples of embodiments is shown in FIGS. 1-3. In various embodiments,device 100 includes a housing 110. The housing may be formed of anysuitable material and of any size or shape suitable for its intendedpurposes. In one or more examples of embodiments, housing 110 is amolded, high-durability plastic or polyethylene and/or may be formed tobe resistant to one or more contaminants. In various embodiments,housing 100 includes at least one generally annular, tubular (e.g., asquare or rectangular tube), cylindrical or conical wall or sidewall 120(e.g., tubular or cylindrical wall) extending between a first opposingend 130 and a second opposing end 140. In various embodiments, housing110 includes a first end assembly member 200 provided about firstopposing end 130 and a second end assembly member provided about secondopposing end 140. In various embodiments, one or both end assemblymembers 200/205 define a cavity or other feature shaped to fit snugly ortightly to or otherwise receive one or both opposing ends 130/140.However, one or both end assembly members 200/205 may be coupled with orto opposing ends 130/140 and/or walls or sidewalls 120 in other ways(e.g., through a threaded connection or by butting the end assemblymembers to or near first and second opposing ends). In variousembodiments, a seal (e.g., an o-ring) is provided between one or bothend assembly members 200/205 and opposing ends 130/140 and/or walls orsidewalls 120. Alternative materials and shapes suitable for thepurposes of the device are also acceptable.

In various embodiments, one or more inlets or in-flow apertures 160and/or outlets or out-flow apertures 170 are defined by housing 110, endassembly members 200/205, and/or sidewalls 120. In various embodiments,the in-flow and out-flow apertures 160/170 are generally defined by endassembly members 200/205 and provided near or about opposing ends130/140 of housing 110. However, the locations of the in-flow andout-flow apertures may vary depending upon the desired results (e.g.,the flow of solution through the device, the timing and/or length oftime thereof, other device configurations, etc.). For example, in-flowand out-flow apertures may be provided through one or more walls orsidewalls, or ends of the device. In addition, the orientation of thein-flow and out-flow apertures (e.g., relative to each other) may bedifferent than that shown in the figures. For example, the in-flow andout-flow apertures may not be parallel relative to each other.

As shown in FIGS. 1-3, one or more fittings or couplings 180 may becoupled or attached to, or integral to, one or more inlets 160 oroutlets 170 defined by housing 110 (e.g., for coupling, connecting ormating housing 110 or device 100 with a supply or inlet line or hose,discharge or outlet line or hose, recirculation line or hose, or otherline or hose). In one or more examples of embodiments, the fluid supplysource line or hose and/or the waste-line or out-flow may be a tube orpipe or other commercially available device used for transporting afluid. In various embodiments, fitting or coupling 180 is tapered toimprove fitment with a line, pipe or hose. However, various couplingconfigurations (including, without limitation, screw or quick connectconfigurations) may be utilized. Further, the fittings or couplings maybe formed of any suitable material and of any size or shape suitable fortheir intended purposes.

At least one pump (not shown) may optionally be provided internally(i.e., within the housing) or externally to the housing to helpfacilitate transfer or movement of fluid or solution through the deviceor a system of devices. The pump may also be used, for example, forcirculation or recirculation.

Referring to FIG. 3, in various embodiments, one or more walls orsidewalls 120 of housing 110 help define at least one cavity 150 havinga cavity wall. In various embodiments, end assembly members 200/205 helpfurther define cavity 150. In various embodiments, cavity 150 issubstantially or entirely annular, tubular, cylindrical, or conical inshape. In various embodiments, cavity 150 is adapted to receive variouscomponents of the device. In various embodiments, the inlets or in-flowapertures 160 and outlets or out-flow apertures 170 pass through housing110 from cavity 150. In various embodiments, apart from the inlets orin-flow apertures 160 and outlets or out-flow apertures 170, cavity 150is sealed or substantially sealed (e.g., from the outside environmentand/or an environment exterior to housing 110) to prevent variouselements (e.g., air or oxygen) from entering cavity 150 and/or variouselements (e.g., a solution) from exiting or escaping cavity 150, exceptthrough in-flow and/or outflow apertures 160/170. It should also benoted that, in various embodiments, flow through cavity 150 may bereversed such that solution enters cavity 150 through out-flowaperture(s) 170 and exits cavity 150 through in-flow aperture(s) 160.

In various embodiments, device 100 includes at least one light tube orsleeve 190. In various embodiments, light tube or sleeve 190 is providedwithin (e.g., within cavity 150) and spaced from wall(s) 120 of housing110. In various embodiments, light tube or sleeve 190 is concentricwithin and spaced from the wall(s) (e.g., cylindrical walls) 120 ofhousing 110. The light tube or sleeve may be provided (e.g., removablycoupled) within the housing in a variety of manners and by employing avariety of means. For example, in various embodiments, as shown in FIG.4, light tube or sleeve 190 is coupled to an end cap 215, and providedor inserted into cavity 150, and end cap 215 is at least partiallycoupled or releasably coupled to and/or near opposing end 130 (e.g., ina cavity defined by first assembly member 200).

Referring to FIGS. 3-4, in various embodiments, light tube or sleeve 190is adapted to disburse, distribute or otherwise transport or providelight over some, most, or all of the length of light tube or sleeve 190and/or some, most, or all of a length of cavity 150.

In one or more examples of embodiments, light tube or sleeve 190 isformed of any material suitable for the purposes provided. In one ormore examples of embodiments, light tube or sleeve 190 is made ofquartz. However, the sleeve may be UV-transparent material, such as, butnot limited to, plastic or glass, or combinations of materials includingsuch UV-transparent and/or UV-translucent material. Alternatively, theUV light source may be used without a light tube or sleeve.

In various embodiments, light tube or sleeve 190 has at least one wallor sidewall that includes a surface and defines a cavity that at leastpartially houses and/or is at least partially adapted to receive one ormore light sources and/or light source assemblies 192 (e.g., anultraviolet (UV) light source, light, or lamp). For example, a UV-lightbulb or bulbs may be provided or inserted into the cavity of the lighttube or sleeve. In various embodiments, a UV source and/or light tube orsleeve 190 is provided and/or extends a distance into cavity 150 ofdevice 100, such that the UV is exposed to a photoelectrode 210 (and/ora photoelectrode 210 is exposed to UV), illuminating or radiating tosome or all of a surface thereof according to the embodiments describedherein.

According to various embodiments, a light source such as a UV bulb isprovided or inserted into a socket provided in end cap 215 and may besecured in position. The UV bulb is further coupled or connected (e.g.,via the socket), or adapted to be coupled or connected, to a source ofpower. In various embodiments, the UV bulb is coupled or connected viaone or more cables or wires to one or more ballasts and/or powersources. In various embodiments, the UV bulb is inserted or otherwiseprovided in first opposing end 130 of housing 110 and the bulb extendsinto at least a majority of light tube or sleeve 190. However, invarious embodiments, the UV bulb may extend only partially or not at allinto light tube or sleeve 190.

In various embodiments, the UV light source is a high irradiance UVlight bulb. In one or more further examples of embodiments, the UV bulbis a germicidal UV bulb with a light emission in the range of 400nanometers or less, and more preferably ranging from 250 nanometers to400 nanometers.

In various embodiments, the ultraviolet light of the UV light source hasa wavelength in the range of from about 185 to 380 nm. In one or moreexamples of embodiments, the light or lamp is a low pressure mercuryvapor lamp adapted to emit UV germicidal irradiation at 254 nmwavelength. In one or more alternative examples of embodiments, a UVbulb with a wavelength of 185 nm may be effectively used. Various UVlight sources, such as those with germicidal UVC wavelengths (peak at254 nm) and black-light UVA wavelengths (UVA range of 300-400 nm), mayalso be utilized. In one or more examples of embodiments, an optimallight wavelength (e.g. for promoting oxidation) is 305 nm. However,various near-UV wavelengths are also effective. Both types of lamps mayemit radiation at wavelengths that activate photoelectrocatalysis. Thegermicidal UV and black light lamps are widely available and may be usedin commercial applications of the instant PECO device.

In one or more additional examples of embodiments, the UV light sourceor lamp is adapted to emit an irradiation intensity in the range of1-500 mW/cm². The irradiation intensity may vary considerably dependingon the type of lamp used. Higher intensities may improve the performanceof the device (e.g., PECO device). However, the intensity may be so highthat the system is UV-saturated or swamped and little or no furtherbenefit is obtained. That optimum irradiation value or intensity maydepend, at least in part, upon the distance between the lamp and one ormore photoelectrodes.

The intensity (i.e., irradiance) of UV light at the photoelectrode maybe measured using a photometer available from International LightTechnologies Inc. (Peabody, Mass.), e.g., Model IL 1400A, equipped witha suitable probe. An example irradiation is greater than 3 mW/cm².

UV lamps typically have a “burn-in” period. UV lamps may also have alimited life (e.g., in the range of approximately 6,000 to 10,000hours). UV lamps also typically lose irradiance (e.g., 10 to 40% oftheir initial lamp irradiance) over the lifetime of the lamp. Thus, itmay be important to consider the effectiveness of new and old UV lampsin designing and maintaining oxidation values.

In one or more examples of embodiments, the light source assembly isdisposed exterior to the housing, and the housing includes a transparentor translucent member adapted to permit ultraviolet light emitted fromthe light source assembly to irradiate the photoelectrode. The devicemay also function using sunlight instead of, or in addition to, thelight source assembly.

In one or more examples of embodiments, and as shown in FIGS. 3 and 4,photoelectrode 210 includes opposing surfaces. In various embodiments,photoelectrode 210 is wrapped, wound, or otherwise provided around thesurface of light tube or sleeve 190. In various embodiments,photoelectrode 210 is provided (e.g., around light tube or sleeve 190)to optimize the distance, separation or spacing between photoelectrode210 and light source 192 (e.g., UV light) and/or tube or sleeve 190. Invarious embodiments, photoelectrode 210 is provided closely or tightlyaround or against the surface of light tube or sleeve 190. In variousembodiments, photoelectrode 210 is coupled (e.g., removably coupled) tolight tube or sleeve 190.

FIG. 4 shows photoelectrode 210 only partially covering sleeve 190 forillustrative purposes. In one or more examples of embodiments,photoelectrode 210 (e.g., a foil photoelectrode) is wrapped, wound orotherwise provided around light tube or sleeve 190 such that a majorityof the UV light or radiation (e.g., from the UV source within light tubeor sleeve 190) is directed at or otherwise exposed to photoelectrode210. In various embodiments, photoelectrode 210 is wrapped, wound, orotherwise provided around light tube or sleeve 190, such that asubstantial portion of the UV light or radiation is exposed to and/ordirected at photoelectrode 210. In various embodiments, photoelectrode210 is provided relatively close to light tube or sleeve 190 such thatless than half (e.g., a relatively small percentage) of any volume ofsolution in or flowing through housing 110 of reactor or device 100 isexposed to light directly from the UV light or UV source.

In various embodiments, photoelectrode 210 is provided relative to lighttube or sleeve 190 such that most of the volume of cavity 150 of reactoror device 100 is between photoelectrode 210 and wall or sidewall 120. Invarious embodiments, photoelectrode 210 is provided relative to lighttube or sleeve 190 such that most of the average cross-sectional area ofcavity 150 of reactor or device 100 is between photoelectrode 210 andwall or sidewall 120. In various embodiments, photoelectrode 210 isprovided relative to light tube or sleeve 190 such that the averagecross-sectional area between photoelectrode 210 and wall or sidewall 120is greater than the average cross-sectional area between photoelectrode210 and light tube or sleeve 190.

In various embodiments, the surface of light tube or sleeve 190 nearestphotoelectrode 210 and the surface of photoelectrode 210 nearest lighttube or sleeve 190 help define a first cross-sectional area and theopposing surface of photoelectrode 210 and a surface of the cavity walldefine a second cross-sectional area, and wherein the firstcross-sectional area is smaller than the second cross-sectional area. Invarious embodiments, the distance from the surface of photoelectrode 210nearest light tube or sleeve 190 to the surface of light tube or sleeve190 nearest photoelectrode 210 is less than the distance from theopposing surface of photoelectrode 210 to the surface of the cavity wallnearest photoelectrode 210.

In various embodiments, photoelectrode 210 is provided around light tubeor sleeve 190 such that it is closer to light tube or sleeve 190 than tosidewall 120 (e.g., to help promote or facilitate flow of most ofsolution in space between photoelectrode 210 and sidewalls 120. Invarious embodiments, the average distance or spacing between a surfaceof photoelectrode 210 nearest light tube or sleeve 190 and a surface oflight tube or sleeve 190 nearest photoelectrode 210 is less thanone-half inch. In various embodiments, the average distance or spacingbetween photoelectrode 210 and light tube or sleeve 190 is less thanthree-eighths of an inch.

In various embodiments, however, the photoelectrode is providedrelatively farther from the light tube or sleeve such that half or moreof any volume of solution in or flowing through the housing of thereactor or device is exposed to light directly from the UV light or UVsource.

In various embodiments, the photoelectrode is provided relative to lighttube or sleeve 190 such that about half or less of the volume of thecavity of the reactor or device is between the photoelectrode and thewall or sidewall. In various embodiments, the photoelectrode is providedrelative to the light tube or sleeve such that about half or less of theaverage cross-sectional area of the cavity of the reactor or device isbetween the photoelectrode and the wall or sidewall. In variousembodiments, the photoelectrode is provided relative to the light tubeor sleeve such that the average cross-sectional area between thephotoelectrode and the wall or sidewall is about equal or less than theaverage cross-sectional area between the photoelectrode and the lighttube or sleeve.

In various embodiments, the surface of the light tube or sleeve nearestthe photoelectrode and the surface of the photoelectrode nearest thelight tube or sleeve help define a first cross-sectional area and theopposing surface of the photoelectrode and a surface of the cavity walldefine a second cross-sectional area, and wherein the firstcross-sectional area is equal or larger than the second cross-sectionalarea. In various embodiments, the distance from the surface of thephotoelectrode nearest the light tube or sleeve to the surface of thelight tube or sleeve nearest the photoelectrode is about equal or morethan the distance from the opposing surface of the photoelectrode to thesurface of the cavity wall nearest the photo electrode.

In various embodiments, photoelectrode 210 includes a conductive supportmember and a film member. In one or more examples of embodiments, theconductive support member is constructed from metal (e.g. titanium orTi). In various embodiments, the film member is nanoporous and includesa thin layer (e.g., 200-500 nm) of titanium dioxide (TiO₂) (e.g., a TiO₂coating) that is provided and/or adapted to function as a photocatalyst.In various examples of embodiments, the film member has an averagethickness in the range of 1-2000 nanometers. In one or more examples ofembodiments, the film member has an average thickness in the range of 5to 500 nanometers.

In various embodiments, the film member is provided on (e.g., coated onor adhered to) the conductive support member. In various embodiments,the film member has a median pore diameter in the range of 0.1-500nanometers and is constructed from TiO₂ nanoparticles. In one or moreexamples of embodiments, the median pore diameter of the film member isin the range of 0.3-25 nanometers. In other examples of embodiments, themedian pore diameter of the film member is in the range of 0.3-10nanometers.

In various examples of embodiments, the film member is constructed froma stable, dispersed suspension comprising TiO₂ nanoparticles having amedian primary particle diameter in the range of 1-50 nanometers. Thenanoporous film may also be deposited by other methods, such as plasma,chemical vapor deposition or electrochemical oxidation. In one or moreexamples of embodiments, the TiO₂ nanoparticles have a median primaryparticle diameter in the range of 0.3-5 nanometers.

In various embodiments, the film member is constructed from a stable,dispersed suspension including a doping agent. Examples of suitabledoping agents include, but are not limited to, Pt, Ni, Au, V, Sc, Y, Nb,Ta, Fe, Mn, Co, Ru, Rh, P, N and/or carbon.

In various examples of embodiments, the nanoporous film member isconstructed by applying a stable, dispersed suspension having TiO₂nanoparticles suspended therein. In various embodiments, the TiO₂nanoparticles are sintered at a temperature in the range of 300 deg C.to 1000 deg C. for 0.5 to 24 hours. Example photoelectrodes may beprepared by coating Ti metal foil. Titanium foil is stable and may alsobe used to make photoelectrodes. One example of suitable Ti metal foilincludes 15 cm×15 cm×0.050 mm thickness and 99.6% + (by weight) pure Timetal foil commercially available from Goodfellow Corp. (Oakdale, Pa.)with a titania-based metal oxide. In various embodiments, the Ti metalfoil is cleaned with a detergent solution, rinsed with deionized water,rinsed with acetone, and/or heat-treated at 350 deg C. for 4 hoursproviding an annealed Ti foil. Annealing may also be conducted at highertemperatures such as 500 deg C.

Following cleaning and/or pretreatment, in various embodiments, themetal foil may be dip-coated. For example, the metal foil may bedip-coated three to five times with an aqueous suspension of titania ata withdrawal rate of ˜3.0 mm/sec. After each application of coating, invarious embodiments, the coated foil is air dried for about 10-15 minand then heated in an oven at 70 deg C. to 100 deg C. for about 45 min.After applying a final coating, in various embodiments, the coated foilis sintered at 300-600 deg C. (e.g., 300 deg C., 400 deg C. or 500 degC.) for 4 hours at a 3 deg C./min ramp rate. The Ti foil may be dippedinto suspensions of titania synthesized using methods disclosed in U.S.patent application Ser. Nos. 11/932,741 and 11/932,519, each of which isincorporated herein by reference in its entirety. In variousembodiments, the optimized withdrawal speed is around 21.5 cm min⁻¹.

In addition, in one or more examples of embodiments of thephotoelectrode, the stable, dispersed suspension is made by reactingtitanium isopropoxide and nitric acid in the presence of ultrapure wateror water purified by reverse osmosis, ion exchange, and one or morecarbon columns. In various embodiments, the conductive support member isannealed titanium foil. Other conductive supports may be employed, suchas conductive carbon or glass. In various other embodiments, thephotoelectrode is constructed from an anatase polymorph of Ti or arutile polymorph of Ti. In one or more examples of embodiments of thephotoelectrode, the rutile polymorph of Ti is constructed by heating ananatase polymorph of Ti at a temperature in the range of 300 deg C. to1000 deg C. for a sufficient time. In one or more examples ofembodiments of the photoelectrode, the anatase polymorph of Ti is heatedat 500 deg C. to 600 deg C. to produce the rutile polymorph of Ti.

In various embodiments, after the titanium support is provided with alayer or film of TiO₂, the composite electrode is air-heated at a hightemperature, giving the nanoporous TiO₂ film a crystalline structure dueto thermal oxidation. It is believed that the instant titania, whenheated at 500 deg C., converts to a crystalline rutile polymorphstructure. It is further believed that the instant TiO₂ heated at 300deg C. converts to a crystalline anatase polymorph structure. In somePECO applications, rutile TiO₂ has substantially higher catalyticactivity than the anatase TiO₂. Rutile TiO₂ may also have substantiallyhigher catalytic activity with respect to certain contaminant such asammonia.

In various embodiments, photoelectrode 210 is modified (e.g., to improveperformance). In various embodiments, photoelectrode 210 (e.g., Ti foil)is modified to increase the surface area of photoelectrode 210 exposedto light such as UV light. For example, photoelectrode 210 may becorrugated or otherwise modified as shown in FIGS. 3-4. As furtherexamples, the photoelectrode may be wavy. The photoelectrode may includevarious other features or microfeatures to help optimize the surfaceexposed to UV light and/or help cause turbulence in fluid or solutionabout the photoelectrode.

In various embodiments, photoelectrode 210 modifications includecorrugating or otherwise modifying photoelectrode 210, conductivesupport member or foil to produce a wave-like pattern (e.g., regularwave-like pattern) on the foil surface. In various embodiments, theheight of a corrugation “wave” is from about 1-5 mm. For example, invarious embodiments, corrugating the foil twice at right angles to eachother produces a cross-hatched pattern on the foil surface.

In various embodiments, photoelectrode 210 modifications include holesor perforations made or provided in photoelectrode 210, conductivesupport member, or foil. In various embodiments, the holes orperforations are made or provided at regular intervals (e.g., 0.5 to 3cm spacing between the holes).

Modifications of the photoelectrode may also include variousmicrofeatures and/or microstructures. Accordingly to variousembodiments, the modifications of the photoelectrode, conductive supportmember or foil may also include various microfeatures and/ormicrostructures that increase the relative surface area of thephotoelectrode and/or increase or promote turbulence about thephotoelectrode. For example, according to various embodiments, suchmicrofeatures and/or microstructures include those that are disclosed inU.S. Patent Publication Nos. 20100319183 and 20110089604, each of whichis incorporated herein by reference in its entirety, or suchmicrofeatures and/or microstructures that are provided commercially fromHoowaki, LLC (Pendleton, S.C.). In various embodiments, themicrofeatures may include microholes. In various embodiments,modifications of the photoelectrode include the formation of nanotubes(e.g., TiO₂ nanotubes) on the photoelectrode, conductive support memberand/or foil such as, for example, those that are disclosed in U.S.Patent Publication No. 20100269894, which is incorporated herein byreference in its entirety.

As a result of the holes, the positioning, the corrugation, and othermodifications, etc., the photoelectrode may help create turbulence influid flowing in and/or through the device. Additionally, one or moreholes may allow oxidants generated or produced on or near a surface ofphotoelectrode 210 to more rapidly and effectively make their way intoor otherwise reach or react with the fluid (e.g., aqueous solution)and/or contaminants therein.

In one or more examples of embodiments, the photoelectrode is in theform of a mesh (e.g., a woven mesh, such as a 40×40 twill weave mesh or60×60 Dutch weave mesh, or a non-woven mesh). Multiple photoelectrodesmay also be used to improve photocurrent and/or chlorine generation.

Referring again to FIG. 3, a counterelectrode (e.g., cathode) 220 isprovided between wall 120 and/or the cavity wall of cavity 150 definedby the housing and photoelectrode (e.g., photoanode) 210. In variousembodiments, counterelectrode or cathode material 220 is in the form ofa foil. However, in various embodiments, the counterelectrode or cathodematerial may be in the form of a wire, plate, cylinder, or in anothersuitable shape or form. In various embodiments, the counterelectrode maybe corrugated and/or have other features to help cause or promoteturbulence in fluid or solution in the cavity.

In one or more examples of embodiments, counterelectrode or cathode 220is constructed from or includes Al, Pt, Ti, Ni, Au, stainless steel,carbon and/or another conductive metal.

In various embodiments, photoelectrode 210 and counterelectrode 220 areseparated by a separator 230. Separator 230 may be used or otherwiseprovided to prevent shorting. In one or more examples of embodiments,photoelectrode (e.g., anode) 210 and counterelectrode (e.g., cathode)220 are separated by plastic or plastic mesh separator 230, althoughalternative separators (e.g., other dielectric material(s) or otherseparators accomplishing or tending to accomplish the same or similarpurposes) may be acceptable for use with the device and system describedherein. In the illustrated examples, and other example embodiments,counterelectrode (e.g., cathode) 220 is placed or otherwise provided“behind” the photoelectrode (e.g., anode) 210 relative to light tube orsleeve 190 or a light source (e.g., UV light source) (i.e., betweenhousing 110 or sidewall 120 and photoelectrode 210).

Positioning of the photoelectrode and counterelectrode in relation tothe relative surface area may be of importance in one or more examplesof embodiments. For instance, a smaller surface area photoelectrodepositioned relatively closer to UV light may generate more photocurrentand chlorine than a larger surface area photoelectrode positionedrelatively farther from UV light. Centering of the photoelectrode oranode (e.g., within the cavity) may also be helpful in optimizing ormaximizing productivity. Likewise, multiple photoelectrodes may beutilized to improve photocurrent, oxidation, and chlorine generation.

As shown in FIGS. 3, 5, and 6, a first terminal and/or terminalconfiguration 240 and a second terminal and/or terminal configuration250 are electrically coupled to photoelectrode 210 and counterelectrode220, respectively. The terminals 240/250 are adapted to receive anapplied voltage bias, potential and/or current provided by a powersource connected or otherwise coupled (e.g., electrically coupled) toterminals 240/250.

Example terminals 240/250, terminal connections, and terminalconfigurations are shown in FIGS. 3, 5, and 6. As shown, terminals240/250 of respective photoelectrode 210 and counterelectrode 220 areprovided about and/or near end assembly members 200/205 and/or opposingends 130/140 of housing 110. However, in other embodiments, theterminals may be provided in relatively closer proximity to each other.

In various embodiments, terminals 240/250 are respectively electricallycoupled (e.g., attached) to counterelectrode/cathode 220 andphotoelectrode/anode 210 (e.g., to form a respective positive terminaland negative terminal). Terminals 240/250 are formed of a conductivematerial, such as a conductive metal. One or more of terminals 240/250may define or be provided with an aperture for ease of connection orcoupling of the terminal to a wire, electrical cable or the like.

As shown in FIGS. 3, 5 and 6, first terminal configuration 240 includesa first member (e.g., a Ti screw) 260 coupled to photoelectrode 210 andprovided through housing 110 (e.g., end assembly member 205). In variousembodiments, first member 260 may be provided through a second member270 electrically coupled (e.g., welded) to photoelectrode 210, andremovably secured to housing 110 with a first fastener 280 such as a hexnut. As shown in FIG. 3, second terminal configuration 250 includes athird member 290 (e.g., a Ti screw) electrically coupled tocounterelectrode 220 and provided through housing 110. In variousembodiments, third member 290 may be provided through or electricallycoupled to a fourth member 300 electrically coupled to counterelectrode220 and removably secured to housing 110 with a second fastener 310,such as a hex nut. In various embodiments, the first member is made of ametal or metals that is resistant to oxidants (e.g., chlorine, hydroxylradicals, etc.) It should be appreciated, however, that any variety ofterminal configurations may be used and any variety of materials andmembers may be utilized. For example, the first and/or second fastenermay be a wing nut or made of another material, the first and/or secondmember may be a bolt, made of another conductive material, etc.

In various embodiments, and as shown in FIG. 6, first member 260 offirst terminal configuration 240 is also provided through a washer 320(e.g., titanium mesh washer) provided near housing 110. In variousembodiments, first member 260 is also provided through a seal 330 (e.g.,a rubber washer or gasket provided on an exterior of housing 110) tohelp prevent leaking of solution from the device or leaking of acomponent such as air into the device. However, the seal may be replacedor supplemented with any type of suitable seal or sealing material orcompound. In various embodiments, the third member may also be providedthrough a washer and/or a seal.

A power supply may also be provided for supplying power to one or moreUV lamps. The power supply, or an alternative power supply may also beprovided for providing an applied voltage between the photoelectrode andcounterelectrode. In one or more examples of embodiments, increasing theapplied voltage increases photocurrent and/or chlorine production. Invarious embodiments, the applied voltage between the photoelectrode andthe counterelectrode is provided to help ensure that electrons freed byphotochemical reaction move or are moved away from the photoelectrode.The power supply may be an AC or DC power supply and may include aplurality of outputs. In one or more examples of embodiments, the powersupply is a DC power supply. Preferably, the power supply is small insize, is durable or rugged, and provides power sufficient to operate oneor more UV-lamps and/or to supply the applied voltage to the electrodesaccording to the previously described methods.

One or more power supplies, in one or more examples of embodiments, maybe connected to a power switch for activating or deactivating the supplyof power. In one or more further examples of embodiments, a powersupply, UV lamps, and or electrodes, may be connected to or incommunication with programmable logic controller or other control orcomputer for selectively distributing power to the UV lamps and/or tothe electrodes, including anodes and cathodes described herein.

In various embodiments, one or more power supplies are external to thedevice. However, one or more power supplies may be internal to thedevice. The power supply(s), in one or more examples of embodiments, maybe connected to a power switch for activating or deactivating the supplyof power. In one or more further examples of embodiments, the powersupply, UV lamps, and or electrodes, may be connected to or incommunication with programmable logic controller or other control orcomputer for selectively distributing power to the UV lamps and/or tothe electrodes, including anodes and cathodes described herein.

Referring now to FIGS. 7 through 13, a second exemplary embodiment of adevice 400 (e.g., a PECO device) or apparatus is shown. In variousembodiments, device 400 includes a housing 410. The housing may beformed of any suitable material and of any size or shape for any of itsintended purposes. In various examples, housing 410 is a molded,high-durability plastic or polyethylene and/or may be formed to beresistant to one or more contaminants. In various embodiments, housing410 has one or more sidewalls 420 extending between first and secondopposing ends 430/440. In various embodiments, housing 410 is generallyannular, tubular, cylindrical, or conical. In various embodiments,housing 410 and/or sidewalls 420 define a cavity 450 having a cavitywall. In various embodiments, housing 410 defines a generally annular,tubular, cylindrical, or conical cavity 450. Opposing ends 430/440 maybe modified or adapted (e.g., threaded and/or grooved) to help couple orremovably couple and/or seal other components or assemblies (such asbulb assembly or module 500 and/or electrode assembly or module 600) tohousing 410.

In various embodiments, device 400 (e.g., PECO device or apparatus)includes a bulb assembly or module 500. In various embodiments, bulbassembly 500 includes a bulb assembly member 510, a light tube or sleeve520, and a bulb socket 530. In various embodiments, bulb assembly 500includes a bulb end cap 540, and a wiring guide or connector 555. Invarious embodiments, light tube or sleeve 520 defines a cavity adaptedto receive a light source or lamp 522 (e.g., a UV light source). Invarious embodiments, bulb socket 530 is provided in a cavity 545 definedby bulb end cap 540 and/or coupled to the bulb end cap 540. In variousembodiments, bulb end cap 540 is coupled (e.g., threaded onto) to lighttube or sleeve 520. In various embodiments, bulb assembly member 510defines a cavity. In various embodiments, the light tube or sleeve 520,bulb socket 530, and a portion of bulb end cap 540 are provided intoand/or through the cavity of bulb assembly member 510, and bulb assemblymember 510 is coupled to bulb end cap 540. In various embodiments, bulbassembly member 510 defines an inlet and/or an outlet 550. In variousembodiments, a tubing or other adapter 480 is provided in theinlet/outlet defined by bulb assembly member 510. In variousembodiments, a light source or lamp 522 (e.g., such as is describedabove) is provided in and/or coupled (e.g., electrically coupled) tobulb socket 530 and/or at least partially housed within light tube orsleeve 520. In various embodiments, bulb end cap 540 defines an apertureinto which wiring guide or connector 555 and/or wiring electricallycoupled to bulb socket 530 and/or a light source may be provided.

In various embodiments, device or apparatus 400 also includes anelectrode assembly or module 600. In various embodiments, electrodeassembly or module 600 includes a terminal assembly member 610, acounterelectrode 620 (e.g., such as is described above), provided arounda photoelectrode 630 (e.g., such as is described above), with aseparator 625 (e.g., such as is described above) provided therebetween,a first terminal 640 coupled to photoelectrode 630 and a second terminal650 coupled to counterelectrode 620. In various embodiments,counterelectrode 620 is provided around and/or outside of photoelectrode630. Each of the terminals 640/650 is coupled to and/or adapted toreceive a voltage, potential or bias. In various embodiments, theterminals 640/650, and/or at least a portion of photoelectrode 630,separator, and counterelectrode 620, are provided within a first cavityor volume defined by terminal assembly member 610. In variousembodiments, terminal assembly member 610 defines a second cavity orvolume 660 at least partially separated from the first volume by adividing wall 665. Terminal assembly member 610 may also be coupled atone end to a terminal end cap 670. In various embodiments, second volume660 may be utilized to at least partially house wiring coupled to aterminal assembly (no shown) provided through one or more apertures individing wall 665. In various embodiments, the terminal assembly andapertures through which the assembly is provided are sealed to preventvarious undesirables or other elements to entering or exiting throughapertures in dividing wall 665.

In various embodiments, terminal end cap 670 defines an aperture adaptedto receive and/or into which a wiring guide or connector 655 and/orwiring electrically coupled to one or more terminals 640/650 may beprovided. In various embodiments, terminal assembly member 610 definesan inlet and/or an outlet. In various embodiments, a tubing or otheradapter 480 is provided in the inlet/outlet defined by terminal assemblymember 610.

In various embodiments, bulb assembly 500 is substantially provided inand coupled to housing 410 at first opposing end 440 of housing 410. Invarious embodiments, electrode assembly 600 is provided within housing410 at or through second opposing end 430 of housing 410 such thatphotoelectrode 630 is provided at least partially around the light tubeor sleeve 520 of bulb assembly 500. In various embodiments, bulbassembly 500 and electrode assembly 600 may be coupled to housing 410 ina variety of ways. For example, one or more of the assemblies may bescrewed onto threads or grooves on housing 410.

In one or more examples of embodiments, photoelectrode 630 is providedaround light tube or sleeve 520. In various embodiments, photoelectrode630 is provided (e.g., around light tube or sleeve 520) to optimize(e.g., minimize) the distance or separation between photoelectrode 630and the UV light and/or tube or sleeve 520. In various embodiments,photoelectrode 630 is provided closely around or near a surface of lighttube or sleeve 520.

In one or more examples of embodiments, photoelectrode 630 (e.g., a foilphotoelectrode) is provided around light tube or sleeve 520 such that amajority of the UV light (e.g., from the UV source within light tube orsleeve 520) is directed at or otherwise exposed to photoelectrode 630.In various embodiments, photoelectrode 630 is provided around light tubeor sleeve 520, such that a substantial portion of the UV light isexposed to and/or directed at photoelectrode 630. In variousembodiments, photoelectrode 630 is provided relatively close to lighttube or sleeve 520 such that less than half (e.g., a relatively smallpercentage) of any volume of solution in or flowing through housing 420of reactor or device 400 is exposed to light directly from the UV lightor UV source.

In various embodiments, photoelectrode 630 is provided relative to lighttube or sleeve 520 such that most of the volume of cavity 450 of reactoror device 400 is between photoelectrode 630 and wall or sidewall 420. Invarious embodiments, photoelectrode 630 is provided relative to lighttube or sleeve 520 such that most of the average cross-sectional area ofcavity 450 is between photoelectrode 630 and wall or sidewall 420. Invarious embodiments, photoelectrode 630 is provided relative to lighttube or sleeve 520 such that the average cross-sectional area betweenphotoelectrode 630 and wall or sidewall 420 is greater than the averagecross-sectional area between photoelectrode 630 and light tube or sleeve520.

In various embodiments, photoelectrode 630 is provided around light tubeor sleeve 520 such that it is closer to light tube or sleeve 520 than tosidewall 420 (e.g., to help promote or facilitate flow of most ofsolution in space between photoelectrode 630 and sidewall(s) 420. Invarious embodiments, the average distance or spacing between a surfaceof photoelectrode 630 nearest light tube or sleeve 520 and a surface oflight tube or sleeve 520 nearest photoelectrode 630 is less thanone-half inch. In various embodiments, the average distance or spacingbetween photoelectrode 630 and light tube or sleeve 520 is less thanthree-eighths of an inch.

As shown in FIG. 14, however, photoelectrode 630 may be spaced fromlight tube or sleeve 520. In various embodiments, photoelectrode 620 isprovided relatively farther from light tube or sleeve 520 such that halfor more of any volume of solution in or flowing through the housing ofthe reactor or device is exposed to light directly from the UV light orUV source.

In various embodiments, photoelectrode 630 is provided relative to lighttube or sleeve 520 such that half or less of the volume of the cavity ofthe reactor or device is between photoelectrode 630 and wall or sidewall420. In various embodiments, photoelectrode 630 is provided relative tolight tube or sleeve 520 such that half or less of the averagecross-sectional area of cavity 450 of the reactor or device 400 isbetween photoelectrode 630 and wall or sidewall 420. In variousembodiments, photoelectrode 630 is provided relative to light tube orsleeve 520 such that the average cross-sectional area betweenphotoelectrode 630 and wall or sidewall 420 is equal or less than theaverage cross-sectional area between photoelectrode 630 and light tubeor sleeve 520. In various embodiments, a surface of light tube or sleeve520 nearest photoelectrode 630 and a surface of photoelectrode 630nearest light tube or sleeve 520 help define a first cross-sectionalarea and an opposing surface of photoelectrode 630 and a surface of thecavity wall define a second cross-sectional area, and wherein the firstcross-sectional area is equal or larger than the second cross-sectionalarea. In various embodiments, the distance from the surface ofphotoelectrode 630 nearest light tube or sleeve 520 to the surface oflight tube or sleeve 520 nearest photoelectrode 630 is more than thedistance from the opposing surface of photoelectrode 630 to the surfaceof the cavity wall nearest photoelectrode 630.

In various embodiments, electrode assembly 600 also includes a spacer700. An example of such a spacer is illustrated in FIGS. 15-18. As canbe seen from FIGS. 15-18, spacer 700 includes an entrance end 710, anexit end 720 and a longitudinal axis running from entrance end 710 toexit end 720. In various embodiments, spacer 700 is divided into twoconcentric portions, peripheral concentric portion 730 and axialconcentric portion 740. In various embodiments, peripheral concentricportion 730 is coupled to axial concentric portion 740 by one or moredividers 750. In various embodiments, dividers 750 and peripheralconcentric portion 730 and axial concentric portion 740 form channels760 through which a solution may flow (e.g., from entrance end 710 toexit end 720, or from exit end 720 to entrance end 710). In variousembodiments, one or more dividers 750 are angled relative to thelongitudinal axis of spacer 700. In various embodiments, one or moredividers 750 have alternative or varying cross-sectional shape fromentrance end to exit end. In various embodiments, a groove 770 (e.g., aconcentric groove) is defined by or otherwise provided in exit side 720of peripheral concentric portion of spacer 700. In various embodiments,a flange 770 (e.g., a concentric flange) helps define groove 770.

Referring again to FIG. 14, in various embodiments, the axial concentricportion of spacer 700 is adapted to receive the light tube or sleeve. Invarious embodiments, the groove defined by the exit side of theperipheral concentric portion of spacer 700 is adapted to receive aportion or an edge of photoelectrode 620. In various embodiments,however, the groove defined by the exit side of the peripheralconcentric portion of spacer 700 is adapted to receive a portion or anedge of photoelectrode 620 and a portion or an edge of separator 625. Invarious embodiments, counterelectrode 630 is provided around the outsideof the flange. In various embodiments, the separator is also providedaround the outside of the flange (e.g., sandwiched between the flangeand the counterelectrode). In various embodiments, the flange of thespacer is adapted to help separate at least a portion of photoelectrode620 and counterelectrode 630 (e.g., to prevent shorting or arcing nearthe edge of the electrode assembly) and otherwise protect at least aportion of photoelectrode 620 and/or counterelectrode 630 from beingbent, damaged or otherwise compromised. In various embodiments, the oneor more dividers are adapted to help direct, redirect, mix, stir orotherwise influence solution as it passes through the channels and/orthe device. For example, the dividers may help to create a spiral flowof solution between photoelectrode 620 and light tube or sleeve 520.Such mixing or flow may be advantageous in many ways. For example, suchmixing or flow may help to mix oxidants generated by the device into thesolution. As another example, such mixing or flow may increase theresidence time of the solution in the cavity of the device for even asolution of moderate velocity. It should also be noted that, while thespacer is shown near an end of electrode assembly, it or any number ofspacers or modified spacers (e.g. spacers not having a flange or groove)may be utilized anywhere along photoelectrode 620 and/or light tube orsleeve 520.

Referring again to and as shown in FIGS. 7-11, in various embodiments,apparatus or device 400 includes housing or control box 700. In variousembodiments, control box 700 may house various components of theapparatus or device 400. For example, in various embodiments, controlbox 700 houses one or more power supplies. In various embodiments,control box 700 houses one or more controls, circuits or switches whichmay be utilized to operate apparatus or device and its components. Invarious embodiments, control box 700 includes one or more circuits(e.g., an H circuit), switches (e.g., a MOSFET) or other devices forreversing a potential or bias across photoelectrode 630 and/orcounterelectrode 620. In various embodiments, control box 700 includes adoor or other component or aperture for ease of accessing componentshoused within control box 700. Control box 700 may be provided withlocks and/or handles or other hardware.

In various embodiments, control box 700 includes or defines a firstconnector 720. In various embodiments, control box 700 includes ordefines a second connectors 710. For example, one or more connectors710/720 may be coupled to or provided through control box 700 to allowinternal components of control box 700 to be electrically coupled to oneor more device or apparatus 400 components provided externally tocontrol box 700. For example, in various embodiments, control box 700includes or defines at least one connector 710 through which wiring isor may be provided or coupled for electrically coupling electrodes620/630 within a device or apparatus 400 to one or more power suppliesprovided in control box 700. In various embodiments, the circuits,switches or other such devices are housed in control box 700 andelectrically connected or coupled to components of the unit 400 (e.g. aphotoelectrode, counterelectrode and/or terminals). In one or moreexamples of embodiments, increasing the applied voltage (e.g., to theelectrodes) may increase photocurrent and chlorine production.

A power supply and/or at least one ballast may be provided in controlbox 700 for supplying power to a UV lamp and/or bulb assembly 500. Theone or more power supplies in control box 700 may be an AC or DC powersupply and may include a plurality of outputs. In one or more examplesof embodiments, the power supply is a DC power supply. The power supplymay be a mountable power supply which may be mounted to control box 700.Preferably, the power supply is small in size, is durable or rugged, andprovides power sufficient to operate at least one UV-lamp included inthe apparatus and/or to supply an applied voltage or bias to theelectrodes according to the described methods.

The power supply or an additional power supply may be connected to theterminals of the electrodes described hereinabove via, for example cableconnection to the terminals, for providing a current, potential, voltageor bias to the electrodes as described in the described methods.

In various embodiments, control box includes one or more visualdisplays. For example, in various embodiments, control box includes avoltage display 730. In various embodiments, control box includes acurrent display 740. One or more of the displays may also display otherinformation. Further, one or more of the displays may display real-timeinformation.

In various embodiments, the device may also include a potentiostat, anda reference electrode in electrical communication with the potentiostat.In one or more examples of embodiments, the device further comprises areference electrode and a voltage control device, such as apotentiostat, adapted to voltage or constant current between thereference electrode and the photoelectrode. In various embodiments, thehousing member is adapted to house the reference electrode.

In one or more examples of embodiments, the device further comprises asemi-micro saline bridge member connecting the potentiostat andreference electrode, whereby housing 110 member is adapted to house thesaline bridge.

In one or more examples of embodiments, the reference electrode isconstructed from silver and is in the shape of a wire.

In one or more examples of embodiments, the potential on thephotoelectrode is held constant relative to a saturated calomelreference electrode by potentiostat, such as EG&G Model 6310. In variousembodiments, the potentiostat is connected to the reference electrodethrough a semi-micro saline bridge, such as available from EG&G, ModelK0065. The saline bridge may be disposed inside the reactor close tophotoelectrode. The current passing through the PECO device may bemeasured.

In various embodiments, the instant potentiostat is a variable currentsource that can measure a voltage between two electrodes. Thepotentiostat can perform a wide variety of electrochemical functions,but the two example functional modes are constant current and constantvoltage. In constant current mode, the potentiostat supplies a userspecified or predetermined current to the electrodes. In constantvoltage mode, it supplies current to the electrodes while monitoring thevoltage. It can then continually adjust the current such that thevoltage will remain constant at a user specified value. A potentiostatcan also be configured to supply pulses.

A temperature probe(s) may also be provided in one or more examples ofembodiments. The temperature probe(s) may be positioned in the containerand/or in the inner box. The temperature probe may monitor thetemperature in the container or in the box or in the fluid within therespective container or box and communicate that temperature reading.Further the temperature probe may be in communication with a shut-offswitch or valve which is adapted to shut the system down upon reaching apredetermined temperature.

A fluid level sensor(s) may also be provided which may communicate afluid level reading. The fluid level sensor(s) may be positioned in thecontainer and/or in the inner box. Further the fluid level sensor may bein communication with a shut-off switch or valve which is adapted toshut off the intake of fluid or engage or increase the outflow of fluidfrom the container upon reaching a predetermined fluid value.

In one or more examples of embodiments, the device includes a carbonfilter adapted to filter chlorine from the water. In variousembodiments, the device includes a computer adapted to send one or morecontrolled signals to the existing power supplies to pulse the voltageand current.

In operation of the foregoing example embodiment, contaminated fluid,such as contaminated water, may be pumped or otherwise provided ordirected into the housing or container. The water may be circulatedand/or recirculated within the housing or container. Multiple units, orreactors, may be connected and operated in series, which may result inincreased space and time for contaminated fluid in the reactor(s) ordevice(s). Upon completion of processing, in various embodiments, thewater exits the housing and container ready for use, or circulated orrecirculated through the device, other device, or system of devices, forfurther treatment or purification.

In various embodiments, in operation, the TiO₂ photocatalyst isilluminated with light having sufficient near UV energy to generatereactive electrons and holes promoting oxidation of compounds on theanode surface.

Any temperature of aqueous solution or liquid water is suitable for usewith the exemplary embodiments of the device such as the instant PECOdevices. In various embodiments, the solution or water is sufficientlylow in turbidity to permit sufficient UV light to illuminate thephotoelectrode.

In various embodiments, photocatalytic efficiency is improved byapplying a potential (i.e., bias) across the photoelectrode andcounterelectrode. Applying a potential may decrease the recombinationrate of photogenerated electrons and holes. In various embodiments, aneffective voltage range applied may be in the range of −1 V to +15 V. Invarious embodiments, an electrical power source is adapted to apply anelectrical potential in the range of 4 V to 12 V across thephotoelectrode and counterelectrode. In various embodiments, theelectrical power source is adapted to generate an electrical potentialin the range of 1.2 V to 3.5 V across the photoelectrode andcounterelectrode (or, 0 to 2.3 V vs. the reference electrode).

For various applications, including, for example fracking fluid orhigh-salinity applications, it may be desirable to reverse (e.g.,periodically or intermittently) the potential, bias, polarity and/orcurrent applied to or between the photoelectrode and thecounterelectrode (e.g., to clean the photoelectrode and/orcounterelectrode, or to otherwise improve the performance of thephotoelectrode, counterelectrode, or device). In various embodiments, byreversing the potential, bias, polarity and/or current, thephotoelectrode is changed (e.g. from an anode) into a cathode and thecounterelectrode is changed (e.g. from a cathode) into an anode.

For example, in various embodiments, initially positive voltage iselectrically connected to a positive charge electrode and negativevoltage is electrically connected to a negative charge electrode. Aftera first period of time, the positive voltage is electrically connectedto the negative charge electrode and the negative voltage iselectrically connected to the positive charge electrode. After a secondperiod of time, the positive voltage is electrically connected back tothe positive charge electrode and the negative voltage is electricallyconnected back to the negative charge electrode. This reversal processmay be repeated as necessary or desired.

The length of the first period of time and the second period of time maybe the same. In various embodiments, however, the length of the firstperiod of time and the second period of time are different. In variousembodiments, the first period of time is longer than the second periodof time.

The length of the first and second periods of time depends on a varietyof factors including salinity, application, voltage, etc. For example,fracking fluid or high salinity fluid applications may requirerelatively more frequent reversal of potential, bias, polarity and/orcurrent compared to fresh water applications. In various embodiments,the lengths of the first period of time relative to the second period oftime may be in a ratio of from 3:1 to 50:1, and in one or more furtherembodiments from 3:1 to 25:1, and in one or more further embodimentsfrom 3:1 to 7:1. For example, in various embodiments, the first periodof time and second period of time is about 5 minutes to about 1 minute.Fresh water applications may require relatively less frequent reversalof potential, bias, polarity and/or current, and the lengths of thefirst period of time relative to the second period of time may be in aratio of from 100:1 to 10:1. For example, in various embodiments, thefirst period of time and second period of time is about 60 minutes to arange of about 1 minute to about 5 minutes.

In various embodiments, the voltage applied between the photoelectrodeand counterelectrode may not change during the first period of time ofnormal potential and during the second period of time of reversepotential. For example, in various embodiments (e.g., where thephotoelectrode includes titanium and the apparatus and/or method areadapted for treatment of fracking or other high salinity solution) thevoltage applied during the first period of time may be less than 9V(e.g., about 7.5V) and the voltage applied during the second period oftime may be less than 9V (e.g., about 7.5V). In other variousembodiments (e.g., where the photoelectrode includes titanium and theapparatus and/or method are adapted for treatment of fresh water) thevoltage applied during the first period of time may be greater than 9V(e.g., about 12V) and the voltage applied during the second period oftime may be greater than 9V (e.g., about 12V).

Maintaining the voltage in the first period of time and the secondperiod of time may help to maintain and/or un-foul the photoelectrode tohelp make it more effective for removing contaminants throughphotoelectrocatalytic oxidation during the first period of time.However, maintaining the voltage under 9V in each period of time maycause a momentary disturbance in the removal of contaminants during thesecond period of time. For a variety of reasons, (e.g., to help minimizeany such disturbance and/or to help cause electroprecipitation and/orelectrocoagulation), in various embodiments, it may be advantageous toapply higher voltages (e.g. voltages greater than 9V) during the firstperiod of time and second period of time. In various embodiments,applying higher voltages helps to promote an electrochemical processsuch as electroprecipitation and/or electrocoagulation during the secondperiod of time, which process can help minimize any disturbance inremoval of contaminants during the second period of time as well asoffer advantages and benefits of such a process.

In various embodiments, the voltage is adjusted to control the rate ofdissolution of the electrode. In various examples of embodiments, thevoltage applied during the first period of time may be more than 9V(e.g., about 12V) and the voltage applied during the second period oftime may be more than 9V (e.g., about 12V). Higher voltages may helpoptimize the effectiveness of the device in certain ways. Highervoltages may also lead to electroprecipitation or electrocoagulation ofcontaminants within or from the fluid. However, such higher voltages mayalso lead to anodic dissolution such as pitting and other degradation ofthe photoelectrode and/or counterelectrode, which may necessitate morefrequent servicing of the PECO device (e.g. replacement of thephotoelectrode (e.g., the foil) and counterelectrode).

In various embodiments, it may be advantageous (e.g., to help limit anyanodic dissolution, or pitting or other degradation of thephotoelectrode) to apply relatively lower voltages during the firstperiod of time and relatively higher voltages during the second periodof time. In various embodiments, e.g., in a fracking fluid applicationusing a photoelectrode and a counterelectrode including titanium, thevoltage applied during the first period of time may be less than 9V(e.g., about 7.5V) and the voltage applied during the second period oftime may be more than 9V (e.g., about 12V for fracking fluid or highersalinity applications, to about 14V for fresh water applications). Invarious embodiments, during application of relatively lower voltageduring the first period of time, contaminants are degraded (or theremoval of contaminants is promoted) by photoelectrocatalytic oxidation,and during application of a relatively higher voltage during the secondperiod of time, contaminants are degraded (or the removal ofcontaminants is promoted) by an electrochemical process such aselectroprecipitation and/or electrocoagulation.

In various embodiments, during the second period of time, thecounterelectrode or sacrificial electrode of titanium is dissolved atleast in part by anodic dissolution. It is believed that a range ofcoagulant species of hydroxides are formed (e.g. by electrolyticoxidation of the sacrificial counterelectrode), which hydroxides helpdestabilize and coagulate the suspended particles or precipitate and/oradsorb dissolved contaminants.

In various embodiments, it is advantageous to apply relatively highervoltages during the first period of time and relatively lower voltagesduring the second period of time. In various embodiments, the voltageapplied during the first period of time is more than 9V (e.g., about12V) and the voltage applied during the second period of time is lessthan 9V (e.g., about 7.5V).

In various embodiments, the main reaction occurring at thecounterelectrodes or sacrificial electrodes during the second period oftime (e.g., during polarity reversal) is dissolution:TI_((s))→Ti⁴⁺+4e ⁻In addition, water is electrolyzed at the counterelectrode (orsacrificial electrode) and photoelectrode:2H₂O+2e ⁻→H_(2(g))+2OH⁻ (cathodic reaction)2H₂O→4H⁺+O_(2(g))+4e ⁻ (anodic reaction)In various embodiments, electrochemical reduction of metal cations(Me^(n+)) occurs at the photoelectrode surface:Me ^(n+) +ne ⁻ →nMe°Higher oxidized metal compounds (e.g., Cr(VI)) may also be reduced (e.g.to Cr(III)) about the photoelectrode:Cr₂O₇ ²⁻+6e ⁻+7H₂O →2Cr³⁺+14OH⁻In various embodiments, hydroxide ions formed at the photoelectrodeincrease the pH of the solution which induces precipitation of metalions as corresponding hydroxides and co-precipitation with metal (e.g.Ti) hydroxides:Me ^(n+) +nOH⁻→Me(OH)_(n(s))In addition, anodic metal ions and hydroxide ions generated react in thesolution to form various hydroxides and built up polymers:Ti⁴⁺+4OH⁻→Ti(OH)_(4(s))nTi(OH)_(4(s)) ⁻→Ti_(n)(OH)_(4n(s))However, depending on the pH of the solution other ionic species mayalso be present. The suspended titanium hydroxides can help removepollutants from the solution by sorption, co-precipitation orelectrostatic attraction, and coagulation.For a particular electrical current flow in an electrolytic cell, themass of metal (e.g. Ti) theoretically dissolved from thecounterelectrode or sacrificial electrode is quantified by Faraday's law

$m = \frac{ItM}{zF}$where m is the amount of counterelectrode or sacrificial electrodematerial dissolved (g), I the current (A), t the electrolysis time (s),M the specific molecular weight (g mol⁻¹), z the number of electronsinvolved in the reaction and F is the Faraday's constant (96485.34 Asmol⁻¹). The mass of evolved hydrogen and formed hydroxyl ions may alsobe calculated.

In various embodiments, it may be advantageous (e.g., to help limit anyanodic dissolution, or pitting or other degradation of thephotoelectrode) to apply certain voltages (e.g., relatively highervoltages) during the first period of time and different voltages (e.g.,relatively lower voltages) during the second period of time. In variousembodiments (e.g., in a fracking fluid application using acounterelectrode including aluminum), the voltage applied during thefirst period of time may be about 6V to 9V (e.g., about 7.5V) and thevoltage applied during the second period of time may be about 0.6V-12V.In various embodiments, during application of relatively higher voltageduring the first period of time, contaminants are degraded (or theremoval of contaminants is promoted) by photoelectrocatalytic oxidation,and during application of a relatively lower voltage during the secondperiod of time, contaminants are degraded (or the removal ofcontaminants is promoted) by and electrochemical process suchelectroprecipitation or electrocoagulation.

In various embodiments, during the second period of time, an aluminumcounterelectrode or sacrificial electrode is dissolved at least in partby anodic dissolution. It is believed that a range of coagulant speciesof hydroxides are formed (e.g. by electrolytic oxidation of thesacrificial counterelectrode), which hydroxides help destabilize andcoagulate the suspended particles or precipitate and/or adsorb dissolvedcontaminants.

In various embodiments, the main reaction occurring at thecounterelectrodes or sacrificial electrodes during the second period oftime (e.g., during polarity reversal) is dissolution:Al_((s))→Al³⁺+3e ⁻Additionally, water is electrolyzed at the counterelectrode (orsacrificial electrode) and photoelectrode:2H₂O+2e ⁻→H_(2(g))+2OH⁻ (cathodic reaction)2H₂O→4H⁺+O_(2(g))+4e ⁻ (anodic reaction)In various embodiments, electrochemical reduction of metal cations(Me^(n+)) occurs at the photoelectrode surface:Me ^(n+) +ne ⁻ →nMe°Higher oxidized metal compounds (e.g., Cr(VI)) may also be reduced (e.g.to Cr(III)) about the photoelectrode:Cr₂O₇ ²⁻+6e ⁻+7H₂O→2Cr³⁺+14OH⁻In various embodiments, hydroxide ions formed at the photoelectrodeincrease the pH of the solution which induces precipitation of metalions as corresponding hydroxides and co-precipitation with metal (e.g.Al) hydroxides:Me ^(n+) +nOH⁻→Me(OH)_(n(s))In addition, anodic metal ions and hydroxide ions generated react in thesolution to form various hydroxides and built up polymers:Al³⁺+3OH⁻→Al(OH)_(3(s))nAl(OH)_(3(s)) ⁻→Al_(n)(OH)_(3n(s))However, depending on the pH of the solution other ionic species, suchas dissolved Al(OH)²⁺, Al₂(OH)₂ ⁴⁺ and Al(OH)₄ ⁻ hydroxo complexes mayalso be present. The suspended aluminum hydroxides can help removepollutants from the solution by sorption, co-precipitation orelectrostatic attraction, and coagulation.For a particular electrical current flow in an electrolytic cell, themass of metal (e.g. Al) theoretically dissolved from thecounterelectrode or sacrificial electrode is quantified by Faraday's law

$m = \frac{ItM}{zF}$where m is the amount of counterelectrode or sacrificial electrodematerial dissolved (g), I the current (A), t the electrolysis time (s),M the specific molecular weight (g mol⁻¹), z the number of electronsinvolved in the reaction and F is the Faraday's constant (96485.34 Asmol⁻¹). The mass of evolved hydrogen and formed hydroxyl ions may alsobe calculated.

The present invention, in one or more examples of embodiments, isdirected to methods of treating an aqueous solution having one or morecontaminants therein to help remove or reduce the amounts ofcontaminants. In various embodiments, the method includes providing anaqueous solution comprising at least one contaminant selected from thegroup consisting of an organism, an organic chemical, an inorganicchemical, and combinations thereof and exposing the aqueous solution tophotoelectrocatalytic oxidization.

In one example of an application of the device described herein, thedevice uses photoelectrocatalysis as a treatment method for frackingfluid. While typically described herein as reducing or removingcontaminants from fracking fluid, it should be understood by one skilledin the art that photoelectrocatalysis of other contaminants can beperformed similarly using the device (e.g., photoelectrocatalyticoxidation or PECO device).

Generally, the method for reducing amount of contaminants in solution orfluid described includes introducing the solution into a housing orcontainer or cell including: a UV light; a photoelectrode, wherein thephotoelectrode comprises an anatase polymorph of titanium, a rutilepolymorph of titanium, or a nanoporous film of titanium dioxide; and acathode. The photoelectrode is irradiated with UV light, and a firstpotential is applied to the photoelectrode and counterelectrode for afirst period of time. In various embodiments, a second potential isapplied to the photoelectrode and counterelectrode for a second periodof time. As a result, the contaminant amount in solution is reduced.

In various embodiments, one or more contaminants are oxidized by a freeradical produced by a photoelectrode, and wherein one or morecontaminants are altered electrochemically (e.g. by electroprecipitationor electrocoagulation). In various embodiments, one or more contaminantsare oxidized by a chlorine atom produced by a photoelectrode. In variousembodiments, one or more contaminants are altered electrochemically(e.g. by electroprecipitation or electrocoagulation).

In one or more embodiments, the apparatus and methods utilizephotoelectrocatalytic oxidation, whereby a photocatalytic anode iscombined with a counterelectrode to form an electrolytic cell. Invarious embodiments, when the instant anode is illuminated by UV light,its surface becomes highly oxidative. By controlling variablesincluding, without limitation, chloride concentration, light intensity,pH and applied potential, the irradiated and biased TiO₂ compositephotoelectrode may selectively oxidize contaminants that come intocontact with the surface, forming less harmful gas or other compounds.In various embodiments, application of a potential to the photoelectrodeprovides further control over the oxidation products. Periodic orintermittent reversal of the potential may help further remove or reducethe amount of contaminants.

The foregoing apparatus and method provides various advantages. Thedevice may be provided in a portable container, permitting on-site wateror fluid decontamination. Further, the device is modular in design andcan be easily combined with other devices as needed. The device is alsoeasy to fabricate and includes electrical connections which are easy tomake. In the apparatus described, the cathode is positioned behind theanode and away from the scouring action of water flow, reducing orlimiting scale accumulation. Additionally, the spacer or separatorprovided between the counterelectrode and photoelectrode reducesshorting caused by contact or proximity of the electrode. These andother advantages are apparent from the foregoing description andassociated Figures.

As utilized herein, the terms “approximately,” “about,” “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claims.

It should be noted that references to relative positions (e.g., “top”and “bottom”) in this description are merely used to identify variouselements as are oriented in the Figures. It should be recognized thatthe orientation of particular components may vary greatly depending onthe application in which they are used.

For the purpose of this disclosure, the term “coupled” means the joiningof two members directly or indirectly to one another. Such joining maybe stationary in nature or moveable in nature. Such joining may beachieved with the two members or the two members and any additionalintermediate members being integrally formed as a single unitary bodywith one another or with the two members or the two members and anyadditional intermediate members being attached to one another. Suchjoining may be permanent in nature or may be removable or releasable innature.

It is also important to note that the construction and arrangement ofthe system, methods, and devices as shown in the various examples ofembodiments is illustrative only. Although only a few embodiments havebeen described in detail in this disclosure, those skilled in the artwho review this disclosure will readily appreciate that manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements show as multiple parts may be integrally formed, theoperation of the interfaces may be reversed or otherwise varied, thelength or width of the structures and/or members or connector or otherelements of the system may be varied, the nature or number of adjustmentpositions provided between the elements may be varied (e.g. byvariations in the number of engagement slots or size of the engagementslots or type of engagement). The order or sequence of any process ormethod steps may be varied or re-sequenced according to alternativeembodiments. Other substitutions, modifications, changes and omissionsmay be made in the design, operating conditions and arrangement of thevarious examples of embodiments without departing from the spirit orscope of the present inventions.

While this invention has been described in conjunction with the examplesof embodiments outlined above, various alternatives, modifications,variations, improvements and/or substantial equivalents, whether knownor that are or may be presently foreseen, may become apparent to thosehaving at least ordinary skill in the art. Accordingly, the examples ofembodiments of the invention, as set forth above, are intended to beillustrative, not limiting. Various changes may be made withoutdeparting from the spirit or scope of the invention. Therefore, theinvention is intended to embrace all known or earlier developedalternatives, modifications, variations, improvements and/or substantialequivalents.

We claim:
 1. A method for removing or reducing the level of contaminantsin a solution, the method comprising: providing a solution into atubular cavity of a device, wherein the cavity of the device houses alight tube, a photoelectrode comprising a primarily titanium foilsupport with a layer of titanium dioxide provided thereon providedaround the light tube, a counterelectrode provided in the space betweenthe photoelectrode and a cavity wall of the device, and an electricalshort-preventing separator provided in the space between thephotoelectrode and the counterelectrode; irradiating the photoelectrodewith ultraviolet light; and applying a first bias to a first terminalcoupled to the photoelectrode and a second terminal coupled to acounterelectrode.
 2. The method of claim 1, wherein the first bias isapplied for a first period of time.
 3. The method of claim 2, furthercomprising applying a second bias to the first terminal and the secondterminal.
 4. The method of claim 3, wherein the second bias is appliedfor a second period of time.
 5. A method for removing or reducing thelevel of contaminants in a solution, the method comprising: providing adevice having a cavity wall which helps define a tubular cavity, whereinthe cavity of the device at least partially houses a light tube, aphotoelectrode comprising a primarily titanium foil support with a layerof titanium dioxide provided thereon provided around the light tube, acounterelectrode provided between the photoelectrode and the cavity wallof the device, and an electrical short-preventing separator providedbetween the photoelectrode and the counterelectrode; irradiating thephotoelectrode with ultraviolet light; applying a first bias to a firstterminal coupled to the photoelectrode and a second terminal coupled toa counterelectrode; and providing a solution in the cavity between thecavity wall and the light tube.
 6. The method of claim 5, wherein thefirst bias is applied for a first period of time.
 7. The method of claim6, further comprising applying a second bias to the first terminal andthe second terminal.
 8. The method of claim 7, wherein the second biasis applied for a second period of time.
 9. A method for removing orreducing the level of contaminants in a solution, the method comprising:providing a device having a cavity wall which helps define a cavityhaving an annular cross-section, wherein the cavity of the device atleast partially houses a light tube, a photoelectrode comprising aprimarily titanium foil support with a layer of titanium dioxideprovided thereon provided around the light tube, a counterelectrodeprovided between the photoelectrode and the cavity wall of the device,and an electrical short-preventing separator provided between thephotoelectrode and the counterelectrode; irradiating the photoelectrodewith ultraviolet light; applying a first bias to a first terminalcoupled to the photoelectrode and a second terminal coupled to acounterelectrode; and providing a solution in the cavity between thecavity wall and the light tube.
 10. The method of claim 9, wherein thefirst bias is applied for a first period of time.
 11. The method ofclaim 10, further comprising applying a second bias to the firstterminal and the second terminal.
 12. The method of claim 11, whereinthe second bias is applied for a second period of time.